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Re: [Amps] Why people don't build amps.

To: amps@contesting.com
Subject: Re: [Amps] Why people don't build amps.
From: Shon Edwards <sre.1966@gmail.com>
Date: Thu, 25 Mar 2010 15:28:41 -0600
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I love this posting.  So true. I fall into the category of "technical, but
not an engineer".  It is true that many of the up and coming ham generation
is not very technical.  I have three sons, aged 9, 9, and 11 (two
technicians and a general) who are new hams this year, and I'm just glad to
get them passing their exams and operating on our equipment in a proper
way.  All we can do is help them to learn if they want to go that way.
Otherwise, I have no solution.

As for me, even though I could build much of what I use, I'd rather buy it
(as the initial poster says, it's often just as cheap to buy the equipment,
especially used) than build it, because with such complex equipment, I'm not
sure I trust myself with hundreds of components.  This is especially true
of, for example, the Elecraft radio kits.  I'd love to own one; I've heard
nothing but good about them.  But what if I botched it somewhere?  And with
components as expensive as amp components, I am definitely worried about
this.  I'd rather buy one new or even used (I found one used (10 hrs. only),
an Ameritron AL-1500 for only $1900 -- truly a bargain) if it looks like
it's in good condition.

73 de Shon KO3U

On Thu, Mar 25, 2010 at 2:56 PM, Cecil Acuff <chacuff@cableone.net> wrote:

>
> ----- Original Message -----
> From: "Roger" <sub1@rogerhalstead.com>
> Cc: <amps@contesting.com>
> Sent: Thursday, March 25, 2010 2:56 PM
> Subject: [Amps] Why people don't build amps.
>
>
> > What are the sources for inexpensive transformers that will
> > do the job?  Not microwave ovens, those things get hot and are not
> > designed for continuous operation. OTOH if one is willing to put up with
> > their short comings they can be paralleled to provide power for a medium
> > size amp.
> ----------------
>
> Interesting post...I have some of the same questions.  Options for
> inexpensive, reasonably sized plate transformers?
>
> -----------------
>
> > But lets say you have access to one of those ultra linear 3CX or
> > 3CPX5000 pulls with fantastic IM in the minus 50 db range,  that can
> > comfortably run the legal limit using all of the drive from your 100
> > watt exciter.
> ----------------------------
>
> Can someone provide sourcing info on reliable, reasonably priced pulls for
> home builders to build with?
> Would love to buy a couple Triodes that don't require sockets.  Would even
> consider tetrodes.
>
> -----------------------------
>
> > Winding the tank coils is easy, but may require sacrificing some copper
> > tubing while learning, or you can find some one who is good at winding
> > coils.  Given the plate impedance, you should be able to find a design
> > to copy which makes placing the taps on the coils much easier.  Also
> > good hefty toroids for the 160 and 75 meter bands is now the way to go.
>
> ---------------------------
>
> I would be more interested in learning how to properly wind, measure and
> tap
> using my GDO than shotgunning it.   I have used the copy cat method and it
> works fairly well but I desire to understand.
> Are there books that describe the process for those of us who are technical
> but not engineers?
>
> What about no band switch and no tapped tank....just a large edge wound
> roller inductor?  Maybe a good bit more expensive but time and loss of
> materials to trial and error are expensive too.
>
> ----------------------------
>
> > Now lets go back to that legal limit issue. I'm not condoning illegal
> > actions, but what is really more ethical, running a 2 or 3 KW amp with a
> > very clean signal,
>
> ----------------------------
>
> I'd much prefer to build and operate an amp capable of 2500W ICS at the
> legal limit and not worry about splatter and stressing expensive
> components.
> (or duty cycle)
>
> Post raises several good questions for those of us that want to homebuild
> but seem to have more questions about doing it right than answers.
>
> I have been inspired by the posts of the last several weeks...to the point
> where I started looking for suitable cabinetry for building.  Purchased two
> 19" rack mounted chassis that had contained 900Mhz radio transceiver
> systems
> from work.  Should make excellent cabinets for home amp projects.  All
> aluminum, probably 18" tall and 24" deep.  Will require some work to add
> and
> remove some internal compartments but good starts for $25.00.
>
> Cecil
> K5DL
>
>
>
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>



-- 
Shon R. Edwards,
BA (German/French/Computational Linguistics),
MA (Computational Linguistics),
AG (Czech Republic)

Radio:
Amateur Call:  KO3U
Commercial radio licenses:
GROL:  PG00016801
GMDSS/O/M:  DB00000391
GMRS:  WQKW341
2nd class radiotelephone:  T2GB064388
Accredited VE:  W5YI, ARRL
ARRL Instructor

1039 N 2575 W
Layton, UT, 84041-7709
USA
e-mail:  sre.1966@gmail.com
phone:  (801) 444-3445
cell:  (801) 336-7635
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